Apparatus for comminuting and drying yeast



Mar. 6, 1923.

Ef KLEIN.

APPARATUS FOR COMMINUTING A-ND DRYING YEAST.

2 SHEETS-SHEET l.

`ORIGINAL FILED MAR. Zf. 1922.

Jv WN. RN

Mar. 6, 1923.

E.` KLEIN. APPARATUS FOR COMMINUTING AND DRYING YEAST.

oRlGmALHLED'r/mmmf1922.

2 SHEETS-SHEET 2.

Paten Niar. 6, 1923.,

RWIN KLEIN, OF VOSLAU, NEAR VIENNA, AUSTRIA, ASSIGNR T THE FLEISCHMANN COMPANY, A CORPORATION OF OHIO.

APPARATUS FOR COMINUTING AND DRYING YEAST.

^ Original application led March 24, 1922, Serial No. 546,502. Divided and this application filed J une 1,7,

. 1922. Serial No.,569,112."

To all whom/t may concern:

Be it known that I, ERWINr KLEIN, a subject of the Kingdom of Roumania, residing at Voslau, near Vienna, in the Republic of Austria, have invented new and useful Im# provements in Apparatus for Comminuting and Drying Yeast, of which the following is a specification. y

My invention relates to improvementsvin the manufacture of pressed yeast, -especially to improvements in drying such yeast, and consistsl of an improved apparatus'for drying pressed yeast Ain order to insure a more uniformly dried final product which will be in a condition better adapted to be influenced and improved by added substances suitable to enhance the effect of suchyeast, than the yeast obtained by the hitherto known drying processes.

The commonly Kknown processes and methods for drying pressed yeast consist in drying yeast by means of air passed through the particles of `yeast which are obtained by dividing the yeast by means of oscillatin sieves, turning devices ofdifl'erent kinds and other means so as to reduce the yeast into a crumby or granulated mass. A still finer subdivision of the particles finto a pulverized state has not been carried out in order to avoid losses incurred by the flying away of the yeast in the form of dust together with the current of air. f

For conserving theJ energy of the yeast during the drying process, the temperature of the current of air employed for this purpose is not allowed to surpass a certain limit.` Generally, this temperature of the current of air used in connection w'ttha crumby or granulated -mass of yeast is not allowed to be higher than 1.0 to l5 degrees jC. in the beginning of the drying process and may beraised to about-30 to 40 degrees in the final period thereof. The pressure .of such air is about 3 atmospheres.

process for'drying pressed yeast is carried out by means of a current of air of higher temperature and of lower pressure than hitherto employed on account of the yeast vAccording to the present invention-thev being brought intp a most finely divided state, preferably in a pulverized or dustlike state.

-' The fact that the yeast is brought into a most finely divided state allows of the use of air of low pressure, because a low pressure is sufcient to bring the air into intimate contact with all fine particles of the yeast, whereas with only coarselydivided yeast, the pressure of the current of air must be materially above that of the atmosphere to penetrate into the interior of the relatively large particles of yeast and to dry them.

Furthermore large quantities of air of more elevated temperature may be passed through the yeast owing to its finely divided 55 state on account( of the dehydration of the yeast taking place so quickly that the particles of the yeast arenot heated to the temperature of the current of air because they are cooled by the losses of heat created by the evaporation of the content of water of lthe yeast particles.

The use of an elevated temperature of the current of air accelerates the drying process and renders it more economical. Contrary to the known processes in which the subdivision is only carried out to such degree that the yeast particles cannot fly away in the form of dust, the process according to my present invention is executed in such a manner that the most feasible quantities of yeast are carried along with the current of air and brought thereby to a collector in which finishing of the drying to the desired content of humidity may be effected (if necessary or desiredfby means of a still more highly heated current of air.

The process is preferably carriedl out 1n the following manner. After a preliminary coarse subdivision of the yeast it is brought into a closed container having a stirring or cutting device acting to bring the yeast gradually into a most finely divided state.

The container is provided with air inlet and outlet ports and is supplied with a current e5 of air of a temperature of about 20 to 30, degrees and having a somewhat elevated pressure. This current of air, which may be dried previously, is passed into the container and throughN the yeast contained therein 100 until the degree of humidity of the yeast is lowered to about 30%. The current of air is then heated to about 50 degrees C. and regulated in such a manner that the particles of yeast brought to the desired degree ofi humidity are carried along and supplied to a special container serving to collect the dust-like particles of yeast. This collector may be provided with heating means theresenti by rendering possible, if desired, a final or additional dryingof the, yeast in the collector.

An apparatus constituting a preferred embodiment of my present invention suitable to carry out the process above described esy consists of a container provided with c nduits servingA for the inlet and outlet-of a current of air and with an intermediate partition-bottom having apertures; the yeast is deposited on this partition-bottom above which a device for pulverizing the yeast is arranged. In order that the current of airmay come from all sides into the most efficient contact with the particles of yeast, the apertures in the intermediate partitionbottom are formed in a special manner, and furthermore provisions are made that the finely divided particles of yeast are carried along with the current of air, leaving the container and being conducted to a collector having compartments into which the particles of yeast of different size are deposited so tha-t a sorting of the yeast is thereby obtained. The compartments of the collector are each provided with heating means, whichv may be' independently regulated-in order to finally or additionally dry the yeast depositdegree if desired and to obvia-te condensing of humidity.

In order that my lnvention may be properly understood, I annex two sheets of drawings in which the preferred embodiment of my apparatus is illustrated.

ig., 1 is a-vertical view, partially in section, through my improved drying device together with the collector. Fig. 2 is a plan of the intermediate partit-ion bottom consisting in essence of two superposed plates containing between themselves apertures feo-r the passa-ge of air. In sector I of this figure the lower plate is illustrated, the upper plate being removed. Sector II shows the. upper plate valone and in sec-tor III the plates in super-position are illustrated. Figs. 3, 4 and 5 are vertical sections on the lines rz-a and b-b and 0 0, respectively of the sectors I, II and III. Fig. 6 is a vertical section on the broken line d-d of Fig. 2.

The container for the reception of the yeast to be dried consists of a receptacle or basin 2 rotatable on its middle axis and having ball-bearings 1; above this receptacle. there is arranged a fixed cover 3 hermetically sealing the receptacle by means of a liquid seal of known kind. Axially of the receptacle a tube 5 extends downwards into which discharges the conduit. 6for the air, which has a concentric groove filled with a liquid in which the tube 5 is immersed in' order to secure an air-tight seal. The fixed cover is provided with anoutlet tube 8 passing to the collector 9. A pulverizing device is rotatably mounted in the depending portion of the fixed cover, and consists, in the illustrated example, of a plurality of cutter-'blades 1() fixed to annular support-s 11, 11 on the shaft 12. The Working edges of these cutterblades are arranged iii a cylindrical surface and are formed in a screw-like manner. The

cover is further provided with Scrapers or turners 13 extending from the lower side of the cover downwards to an intermediate partition bottom 15 mounted in the receptacle 2 and having vertical apertures 14. These Scrapers plough and turn the yeast deposited on this bottom 15 when the receptacle is rotated. I

The collector 9 consists of a plurality of concentric shafts 16, 17, 18 enlarging conically on one end and discharging on the opposite ends into a series of compartments 19, 20, 21, respectively, each of which is provided with heating means, for example with. steam-serpentines 19a, 20a and 21, respectively. The shafts together with the compartments are included within a common casing 22. This casing which is provided with doors (not shown) for the removal of t-he collected and dried yeast from the compartments 19, 20, 21 which are also provided with suitable doors (not shown), encloses also the upper conical ends of the shafts and is provided at such upper portion with aheating device asindicated at 23 for preventing condensation. Bafile-plates 24, 25 are fixed on the upper wallof the exterior shaft and extend into the conical dis charge ends of the other shafts. Air outlet ports 26 a-rearranged in the top plate of the casing, surmounted by a roof-like cover 27.

The operation ofthe apparatus is as follows: The yeast to be dried is deposited through an `opening l (not shown) in' the cover 3 on the intermediate partition bottom 15 of the receptacle 2 which is then rotated by means of a shaft 28 and of a toothed wheel 29 mounted on this shaft and of a toothed-wheel 30 provided at the outer circumference of the receptacle. The shaft 28 may be driven from any source of power. The shaft 28 simultaneously actuates, for example by means of the worin-gear within the casing 3,1, the shaft 12. rotatably mounted in the cover so that the cutter-blades l() fixed thereon are brought into rotation.

' By means of the conduit 6 suitably preheated air is supplied and is passed through vBt) the apertures 14 and through openings existing between the superposed plates and comes then into Contact with the yeast,v

thereby drying the same.

By the rotation of the receptacle 2 and of the intermediate partition bottom 15 the yeast deposited thereon is partly lifted and turned by the fixed scraper 13, the ends of which may have the form of rakes; simultaneously the yeast is gradually cut into smaller and smaller particles. The cutters also act as turning and distributing devices by partly turning, lifting and distributing the yeast.

The air flows .out through the conduit 8 to the collector 9 and carries with it such small particles of yeast, the drying and pulverizing of which has taken place to such an extent as to allow their being swept away by the current of air.

The particlesof yeast carried away by the current of air are depositedI for the most part in the compartment 19part of the yeast, namely the lighter particles, is lifted by the current between/"the walls of the shafts 16 and `17 #tas indicated in Fig. 1 by arrows), is brought after passing the bailleplates 24 into the spacev between shafts 17 and 18 and falls down into the compartment 20; the still lighter particles are again lifted by the current and are linally deposited, after passing the baille-plate 25, in the compartment 21.

On account of the repeated change of the direction of the outflowing air caused by the baille-plates, the particles of yeast carried along with the air are separated in their totality from the air so that practically air without any yeast particles leaves the casing 22 through the opening 26.

The collector therefore acts as a device for separating -the smallest dust-like particles of yeast from the current of air, so that losses are obviated. ln order to free -the walls of the shafts from any particles of yeast adhering thereto and to collect them in the respective compartment, a vi-` brator is provided consisting of a stem 32 ticles ofyeast adhering to the walls o lactuated by a cam 33 onthe shaft 28 so as to be pushed againstthe wall of the outer' shaft 16. A. tension spring brings thestem backto its original position. By the slight tapping of this stem upon the wall any alp t e shafts and to the baille-plates are caused to fall down. Each compartment 19, 20, 21 is independently heatable, as already stated, for example by means 'of steam`pipes 'or the like for a further drying treatment of the yeast. In order to. obtain a good uniform drying of the yeast it is necessary that the air come into an intimate contact with all sides of the yeast particles. On account of the humidity the yeast tends to form lumps and to choke the openings for the passage of air thereby preventing a uniform contact of the air with and an efficient dryingof the yeast. According to the invention Vthe uniform contact of air under a low pressure with the yeast is obtained by a-special shape of the intermediate partition bottom on which the yeast to be dried is deposited. Y

This bottom essentially consists of two superposed plates 35, 37 which have therebetween a series of channels 39 in the shape of dies, each series of channels being provided in a sector of the plane, the lower I and upper plate being divided into a series of sectors. The surface of the lower plate consists in each sector of a series of bevelled or tapered planes 36, which are oblique and of which every twoadjacent planes, form togetherroof-like surfaces. In each sector part of the upper plate 37 -is removed so that an opening 40 is created. One edge of the remaining part of the upper plate is zigzag-lined and preferably provided with teeth 33, whereas the other radial edge is unbroken.

AThe form of the inclined or Ibevelled planes 36 of the lower plate 35 is diagram- Inatically shown in sector -ll of Fig. 2, in which the section-lines of horizontal planes withthe bevelled planes 36 of the lower plate are indicated by the zigzag lines f-f, g--g IL IL.

The lower sides of the points of the teeth v38 rest on the lower plate 35 along lines of the same level, i. e. along zigzag lines. 0n account of the 'bevel of the planes of the lower plate the interstices 39 (Fig: 5) between these two plates,(the lower 35 and the upperplate 37), have the shape of a die lying in the direction of concentric cycles. The discharge ends of these die-like channels 39 are dividedl by the teeth 38 of the upper plate 37 into a plurality of separate discharge openings. The current of air supplied by-the conduit 6 passes through. the vertical ports 13 of the lower plate and enters the channels 39 between the lower and upper plate, discharging in. the 'yieast deposited on the upper-plate. On account of the zigzag-form of the discharge end of the channels 39 a relatively large cross-section of discharge is seeuredand the current is subdivided 'by the teeth' 38 into lsingle streams blowing in different directions. For further subdividing and distributing the current of air the upper-plate 37 may be y 4'provided on its lower rside with ribs resting direction of concentric cycles and pass obliquely from below to above, thereby enabling removal of the yeast from the discharge openings when the yeast is ploughed by the Scrapers on rotating the receptacle 2.

. To prevent escape of air between the edges of the rotating receptacle and the fixed cover the latter is provided with an annular plate 42 the lower edge of which extends into a groove 4 of the receptacle 2, which groove is I filled with liquid. By these means any loss of yeastis obviated.

A branch 43 of the lair conduit 6 supplies air in the annular space between the plate 42 and the sides of the receptacle and otthe c'over so that the samear pressure is created therein, thereby assisting the seal formed by the liquid.

JThis application is divided from m'l application for United States Patent erial No. 546,502, filed March 24, 1922.

What I claim as my invention and desire to secure byg Letters Patent is:

1. In an apparatus adapted for drying compressed yeast, the combination of areceptacle having a fiat bottom capable of supporting compressed yeast during the drying operation, means for passing a current of an aeroforrn drying fluid through the receptacle inl contact with the yeast, and means for mechanically subdividing the yeast upon the bottom of the receptacle, said subdividing means and the bottom of the receptacle being .movable with respect to each `other about a vertical'axis and said subdividing means including a comminuting member closely spaced from the bottom of the receptaclefand extending across substantially its entire width.

2. Apparatus for drying pressed yeast comprising a container consisting of a rotatable receptacle and a superposed fixed cover, an air-tight seal betweeen this receptacle and the cover, the rotatable receptacle having an intermediate partitionIv bottom.

provided with ports, means for mechanically dividing the yeast fed to the said -zbottom, means for the supply of a current of air 'below this bottom and means for the outflow of air from above said bottom.

3. Apparatus for drying pressed yeast comprising a container consisting 'of a rotatable receptacle, and a superposed fixedA cover, the rotatable'receptacle.'having an in.

termediate partition bottom provided vwith ports and the fixed cover carryiing means for mechanically subdividing the yeast fed to the bottom, means forthe supply of a current of air below this bottom and means for false bottom and means for. passingl a our? rent of air therethrough in anr upward direction, with means for mechanically subdividing the yeast' upon said bottom, said sub-l dividing meanscomprising cutter blades mounted on a rotating shaft `with their cutting edges arranged spirally in a cylindrical surface in uniform close proximity to said bottom. v

5.' Apparatus for drying pressed yeast comprising a container consisting of a rotatable receptacle andv a superposed fixed cover, an air-tight seal between this receptacle and the cover, the rotatable receptacle having 'an Iintermediate partition bottom 'provided with ports, means for mechanically dividing the yeast fed to the said bottom, means for the supply of a current of air through said bottom and also thro-ugh a separate air inlet port positioned above said .bottom and means for the koutflow of air `which the yeast to be dried i's deposited, this bottom consisting of two superposed plates leaving between themselves oblique channels, formed by bevelled and roof-like planes on the upper surface by the lower plate and of the even underside of the upper late. p 7. In an a paratus for drying pressed yeast, a contamer for the yeast, means for the inlet and outlet of a current 0I air into and out of the container, an intermediate partition bottom in the container upon which the yeast to be dried is deposited, this bottom consisting of two superposed plates leaving between themselves oblique channels, formed by bevelled and roof-like planes on the upper surface by the lower plate and of the even underside of the upper plate.

8. In an apparatus for drying pressed yeast, a container for the yeast, means for the inlet and outlet of a current of air in and out of the container, fan intermediate bottom .in the container upon which the yeast to be dried is deposited. this bottom consisting of two superposed plates. the

lower plate having a series of bevelled and roof-like planes on its upper surface uniformlydistributed over sections of the plate,

ill

the upper plate having' an even underside and being partly interrupted in conformity with the sections of the lower plate, the underside of the upper plate confining channels with the bevelled and roof-like planes ofthe lower plate, leaving interstices between suchV surfaces, discharging through the interruption to the upper side of the upper plate.

9. In an apparatusfor drying pressed yeast, a container for the yeast, means for the inlet and outlet of a current of air into land out of the container, an intermediate partition bottom in i the container upon which the yeast to be dried is deposited, this bottom consisting of two superposed plates,

the lowerplatehav'ing a 'series of bevelled and roof-like planes on its upper surface uniformly: ldistributed over sectlons of the plate,the upper plate having an evenunderside and being partly interrupted in conformity with the sections of the lower late, the Junderside of the upper-plate con ning channels with thev bevelled and roof-like planes offthelower plate, leaving interstices `,between such surfaces, discharging through the'interrpt'ion to the upper side of the upper plate,` the edge of the upper plate bordering tl'ie interruptions being saw-like subdividethe' current of air into separate streams. 10. In'an apparatus for drying pressed yeast, a container having air inlet and out' let conduits, means for mechanically pulverizing theyeast to be dried, means for passing 'a current of air through the yeast l'and means fori'collecting the partly dried yeast carried away by the current of air, said means consisting of a series of containershafts, arranged at a distance-from the drying container and connected therewith, each container-'shaft being provided with independent heating means and communicating with the other shafts so as to allow a sorting and depositing of the'particles of yeast carried along with. the current of air.

11. In an apparatus for drying pressed yeast, a container having inlet and ,outlet openings, means. for mechanically pulv'erizing the yeast to be dried, means forpassing a /current of air through the yeast -and .means for collectin the partly dried yeast carriedA away by t e current vof air, said means consisting of a series of containershafts, arranged at a distance from the drying container and connected therewith, ythese shafts being cylindrical and arranged concentrically andhaving conical enlargements on one end and dis'charV ing into vclosed compartments, each of `wh1ch is, independently heatable, and baiil'e-plates extending into and parallel to"thelcon1cal enlargements of the shafts.

"12. In an apparatus for drying pressed yeast, al container having air inlet and outlet ports, means for mechanically pulverizing theyeasttoA be dried,'means for passing a currentof air through the yeast and means `forcollecting the partl dried yeast carried away by .the current o airsaid means con-v 13. Apparatus for drying 'pressed yeast.v

consisting of a rotatable receptacle and of a fixed cover, an annular plateifixedto and surrounding the border of thecover and immersing into a liquid, contained'in a groove of the dish, means for 'admitting air under pressure into the annular chamber between the plate and the cover border.`

DR. ERw'IN KLEIN. 

